Hi gang. I´ve been struggling with the Fuzz Face, eventually I tried the Fuzzcentral Axis Face, a silicon, negative ground variation. Works rather well, but I never liked the Face´s high end, too fizzy. That schem uses a 0,033 uF cap across the original 330R (1K2 in this schem) to tame high end. But still too fizzy. When going to sleep, a lightbulb went off, and I came up with this tone control (before this I tried LP filters at the output, but they didn´t satisfy me):
(http://i68.photobucket.com/albums/i5/Morocotuco/Si-Fuzz-Face-TONE.jpg)
Works quite well, tames the high end, gives, at least to me, much more versatility to this classic schem.
Now, I can´t believe I´m smart enough to be the first one to do this... anyone ever tried this idea? I, at least, never saw it anywhere...
Also, anyone sees any disadvantage to this mod? I mean, it works, but I don´t know if it causes any sort of trouble, I´m just a hack with a breadboard!
It should be fine because the net result is still the circuit seeing a cap of some value. Neat!!
-Joe Hart
Weirdly enough, I thought of the same idea the other day after adding an input blend to a fuzz circuit. Great minds think alike! ;D I haven't tried yet though. How much tonal variation does the blend give?
FWIW
This was first with the Low Pass and the 100 ohm emitter/10K collector.
http://www.diystompboxes.com/pedals/gusFuzzFace.gif
http://www.diystompboxes.com/pedals/3tran.JPG
http://www.diystompboxes.com/pedals/gusJH2mod.gif
http://www.diystompboxes.com/pedals/rocket.JPG
http://www.prodigy-pro.com/diy/index.php?topic=32333.0
some sound samples
Nice schems Gus, I haven´t seen your work before. Would you care to explain the function of the 100 Ohm resistor in the emitter of Q1? I´ve never seen that before. Don´t be mad, sharing is like that... ;D
Chugs, it has a nice range of high end taming. At one extreme it´s the usual mosquito cloud, at the other it gets quite creamy.
Ariel
That is the first time I've seen that configuration used in that place of the FF.
I've used a cap across the collector resistor and even the input and output blend
caps but I had not thought of the cap across the collector as a blendable cap.
Nice one!
nice thinking.
interesting how beautiful solutions and ideas come to us when we are half asleep, waking up, dreaming.
Yep Joe, half asleep is good.
;D
Not ALL the time, mind you. But, maybe that´s the key to Keith Richard´s success?
:icon_mrgreen: :icon_mrgreen:
yeah , that looks like a keeper. but i'm not sure how much more abuse my fuzz can take :icon_mrgreen: one more mod.
Quote from: joegagan on April 24, 2010, 01:46:40 PM
interesting how beautiful solutions and ideas come to us when we are half asleep, waking up, dreaming.
That's happened to me many times. But it's not always DIY related stuff.
Clever idea for the tone control. :icon_cool:
Hi
the variable roll-off is a super cool idea.
my 2c worth on the 10k/100ohm method...
The small emitter resistor (e.g. 100 ohm) seems to be a good idea, and means that you could use a garden-variety Si transistor as Q1 instead of a Ge without getting massive gain. But consider what this does to the biasing, input resistance and tone. If, for the purposes of comparing bias, we imagine an NPN, negative ground fuzzface, the base of Q1 is at 0.3 V (because it is one p-n junction above ground). Si fuzzfaces have the base at 0.7 V. Therefore, a Ge fuzzface has a lot less headroom and there is more clipping and the clipping is more asymmetrical than for an Si transistor with a similar hFE (e.g. a 2N2369A). Also, the input resistance is low (proportional to the hFE and about 15k-20kohms), giving creamy tone and significant sag and bloom.
Now, add an emitter resistor. The bias rises by the Ie x Re (about 0.05 V in the case or 10k/100ohms) and the asymmetry in the clipping falls a bit. The input resistance is close to the hFE x the Re (typically 40k). This means there's a lot less sag and bloom (hardly any compared with a low hFE transistor). These may be reasons why Ge appeals to so many people, even though their availability and quality are low and the price and nuisance value is high.
cheers
Bien pensado Ariel!
You gave me another idea I'll try tomorrow: I'm going to replace the 330R with a 500R or 1k pot, wiper -> cap -> Vcc.
mac
Gracias Marcelo! Muy de vez en cuando la neurona se activa...
:icon_mrgreen:
You mean, R and cap in series? What would that do? Hmmm.
Seems like someone did the variable cap deal with the big electrolytic on the Fuzz control some time back... May have been Joe. The input cap also.
Seems to be enough places on the FF to add 1st order low pass filters that they end up cascaded for 2nd 12db/oct or 3rd 18db/oct order roll off. :icon_cool:
QuoteYou mean, R and cap in series? What would that do? Hmmm
No, the cap is in parallel with part of the pot. I tried it today and it works fine.
500R linear
vcc ------//////----------//////------Q2 collector
| 8k2
=== 47nf
|
vcc ---------
mac
Oh, ok. Functionally it´s the same as my mod? Or different? how does it sound?
I´ll see if I can make some sound clips of mine.
EDIT: Ok, some quick, out of tune, semi awful sound clips. One straigt into the computer via mixer:
http://www.zshare.net/audio/75460839a2acfda4/
Fuzz Face tone test no amp sim.mp3 - 2.56MB (http://www.zshare.net/audio/75460839a2acfda4/)
First with tone 100%, then half, then 0%. Some guitar vol control fiddling. P 90´s mid position.
Same through a software amp sim, clean amp setting:
http://www.zshare.net/audio/75460927958e8946/
Fuzz Face tone test w amp sim.mp3 - 2.56MB (http://www.zshare.net/audio/75460927958e8946/)
Yep, I'm diggin' it. Sounds nice. :icon_smile:
Going to have to try it.
It works different because when cap is on the vcc side it does not cut highs.
mac
So it goes from "not cutting highs at all" to a variable amount of cut? Is that right? In essence, a tone control with more range?
QuoteSo it goes from "not cutting highs at all" to a variable amount of cut? Is that right? In essence, a tone control with more range?
Yeap. I used a 47nf but can be increased to 100nf to cut even more highs.
Here is the schem (have you ever tried to draw schems using Paint? :P)
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=42952&g2_serialNumber=1)
mac
Coool!
Paint is a pain in the a$$
:P
I´m gonna try your version of the Mod marcelo, see how I like it. Report later.
Hey, I stumbled on this thread yesterday while trying to find a novel tone control for my FF. I had the Dunlop JD-F2 reissue version and had heavily modified it over the years, but it still wasn't cutting it at all. It was muddy and had barely more than unity output with everything maxed, so I decided to totally rebuild it using the Axis Face PCB layout from Fuzz Central. I was going to reuse the Ge transistors and, of course, the enclosure, but came to find out that the trannies I had were ridiculously leaky and too high gain to boot (which was probably most of the problem,) so I went with a couple NPN Si I had laying around with gains of about 80 and 140 for Q1 and Q2, respectively. I used Marcelo's tone control with a 1kB pot and 47 nF cap initially, liked it, but felt I needed to be able to roll back more high end (I had also decreased the input cap to 1 uF, the emitter bypass cap to 10 uF, and the volume pot to 100kA, making the whole thing thoroughly more trebly,) so I changed the tone cap to 100 nF and that completely hit the spot. I had been using the SWTC, but it was loading the output far too much for my liking. Marcelo's design (and, of course, Ariel's initial concept,) is ingenious: instead of simply dumping highs after the fact, it adjusts the gain of the higher frequencies, much like a Dallas Rangemaster. It has significantly less impact on the output level. Also, in place of the fuzz control, which I've always found basically useless and just hard-wired on at 1.5k, I used the Fulltone-style "smooth" control, 100kB as a variable resistor on the input. Simply put, it's super useful, when you roll it back you get great backed-off cleanish fuzz that you can set and have available when the effect is switched on, rather than fiddling with the guitar's volume, though that also has a good, wide range of effect on the sound. Add in an outside-accessible bias trim pot and sockets for the trannies and caps and I have the most versatile, sweet-sounding fuzz I've ever played. Not only that, but it has loads more output than most others I've tried. Usually you have to dime the volume and fuzz to get anywhere near enough volume to cut through a mix. All of this just confirms, in my very humble opinion, that the fetish for Ge transistors, despite their leakiness and temperature instability, is more about just knowing they're in there than any inherent sonic superiority. Of course, I do not have "golden ears", so salt that however much you like.
Long story shortened slightly, a big thank you to Ariel, Marcelo, Mike Fuller, Phillip Bryant, and the venerable R.G. Keen for his ever-enlightening Technology of the Fuzz Face article from which I drew most of my inspiration.
NOte that this high cut control can be implemented on all collectors/drains, or emiters/sources in buffers.
mac
Yeah, I guess it's been staring me in the face in the Big Muff's base to collector bypass caps, maybe it would be interesting to implement this idea in the Muff and forgo the traditional tonestack which I've never liked.
QuoteYeah, I guess it's been staring me in the face in the Big Muff's base to collector bypass caps, maybe it would be interesting to implement this idea in the Muff and forgo the traditional tonestack which I've never liked.
Add the Axis Face bass control at the front.
Or you could try the tonebender 3 tone stack ;) :icon_eek:
Just replace the 15k on any of the first 3 stages with a 18k + 4k7 and add the rest of the tone control parts. If you take a look at the TB3 schem you'll figure it out.
mac
Next on the old breadboard: a muff, possibly just the first three stages, minus the normal tonestack, sustain wired full-on and I'll try these tone control ideas, see how it works out. I've been wanting to make something smaller and simpler than my frankenmuff, good as it is.
wow,cool, you are getting very close to our experiment from 2010. we wired the sustain knob full up and got rid of the tone stack and a few other things. it sounded very good to me. i have a few vids and a schematic on this thread: ( didn't mess with the tone at the diode/cap loops tho)
http://www.diystompboxes.com/smfforum/index.php?topic=83920.0
Nek, glad you got some use out of this! I implemented this in a Fuzz Face, and later made another one with the Big Muff tonestack, and this highs filter sounds so much better than the Big Muff one, at least to me.
Mac, I just built a Tonebender MK III. Super cooooool!!!! Now, I´ll add the MK III tonestack to a Fuzz Face, to see how it works.
Quotewow,cool, you are getting very close to our experiment from 2010. we wired the sustain knob full up and got rid of the tone stack and a few other things. it sounded very good to me. i have a few vids and a schematic on this thread: ( didn't mess with the tone at the diode/cap loops tho)
Joe, that's sick!!! :icon_eek: :D
You could omit the recovery stage to simplify things even more, although gain will decrease a bit.
QuoteMac, I just built a Tonebender MK III. Super cooooool!!!!
TB3, one of my favourite fuzzes.
I'm working again on my simplified silicon version, stay tuned.
QuoteNow, I´ll add the MK III tonestack to a Fuzz Face, to see how it works.
jaja buena idea!!!
mac
Quote from: mac
Joe, that's sick!!! icon_eek Cheesy
You could omit the recovery stage to simplify things even more, although gain will decrease a bit.
thank you!
yes, that was suggested by several people back on that thread but i really liked the hot output level. still surprises me how much i like the tone and sustain on those videos even two years later.
Quote from: mac on April 28, 2010, 11:43:08 PM
QuoteSo it goes from "not cutting highs at all" to a variable amount of cut? Is that right? In essence, a tone control with more range?
Yeap. I used a 47nf but can be increased to 100nf to cut even more highs.
Here is the schem (have you ever tried to draw schems using Paint? :P)
(http://www.aronnelson.com/gallery/main.php?g2_view=core.DownloadItem&g2_itemId=42952&g2_serialNumber=1)
mac
I was looking at this and also at the Stupidly Wonderful Tone Control 2 (http://www.muzique.com/lab/swtc.htm) being discussed in http://www.diystompboxes.com/smfforum/index.php?topic=97858.0 and I am confused. How is this (above) a treble-cut control when the SWTC2 is a treble-boost control. They look like they are doing the same thing to me, but I am not well versed in these things. Can someone enlighten me?
In my schem, when the pot is on the right side (connected to the 8k2 resistor), the 0.047uf cap is a low resistance path for high frequencies to Vcc, and since the battery resistance is very small, to ground. The other path is through the 0.01uf cap, but it has a bigger impedance.
When you set the pot to the left side the cap is shorted, no treble cut at all.
mac
Thank-you mac. I didn't know that the + battery connection could function as a low resistance path to ground in this manner. I've learned something new - yay! Now it makes sense. Would using a power supply instead of a battery change things at all (i.e. do typical 9V pedal power supplies have a low internal resistance similar to a 9V battery)?
That axis face schematic needs a serious re-draw. It's like trying to read english characters written top to bottom. Borderline not worth the effort.
Anyhow, just to throw another orange at the wall - consider active 2-pole low pass filtering. It's much different sounding than passive filtering. You can only get so much attenuation of high frequencies with a passive filter of any kind. I entered the stompbox building world because I was tired of distortions that had a high end that could not be dialed in properly.
Active filtering - namely, 2-pole LPF with a variable cutoff frequency rather than variable amount of cut - often seen in it's core essence in 'speaker simulation' but with a static cutoff frequency, maybe some peaking, and cascaded (values should be tweaked, LTspice is worth the time to learn), can be much more subtle in how it shaves the fizzies, or smooths things out, and to boot, it can be configured to have absolutely no effect on the audio range, all variable via a dual gang pot (for example)!!!
QuoteWould using a power supply instead of a battery change things at all (i.e. do typical 9V pedal power supplies have a low internal resistance similar to a 9V battery)?
A few ohms will not make much difference.
mac
Quote from: mac on June 13, 2012, 08:55:36 PM
A few ohms will not make much difference.
Thanks.